In a magnetic tape, it is general that writing and reading of data are performed by a sequential access method. In the sequential access method, data is sequentially written or read from the head of the magnetic tape. On the other hand, in recent years, as disclosed in Reference Literature 1 (Japanese Laid-open Patent Publication No. 2013-161185), an access method (hereinafter, also referred to as a file access method) adapted to a file system has been developed as a method for accessing a magnetic tape. Since the file access method for a magnetic tape is based on a standard regarding LTFS (Linear Tape File System), even in the case of a magnetic tape, for example, data can be read and written such that data stored in a hard disk is read and written.
A format of a magnetic tape adapted to the sequential access method is different from a format of a magnetic tape adapted to the file access method. A magnetic tape drive apparatus that reads and writes a magnetic tape has a type capable of reading and writing various kinds of magnetic tapes having formats different from the above formats. Such the magnetic tape drive apparatus operates as follows when reading and writing the magnetic tape. That is, when the magnetic tape (hereinafter, also referred to as a LTFS type magnetic tape) of the format adapted to the file access method is loaded, the magnetic tape drive apparatus generates a logical device adapted to the file system. A host apparatus (for example, a server or a PC (Personal Computer)) connected to the magnetic tape apparatus recognizes that the connected magnetic tape drive apparatus is an apparatus adaptable to the file system.
Then, when the magnetic tape is unloaded for the purpose of a change and the like of the magnetic tape, the magnetic tape drive apparatus deletes the logical device. In this way, a host apparatus does not recognize that the magnetic tape drive apparatus is the apparatus adapted to the file system.
In this state, when the magnetic tape drive apparatus loads a non-LTFS type magnetic tape, no logical device is generated. Therefore, the host apparatus does not still recognize that the connected magnetic tape drive apparatus is the apparatus adapted to the file system.
On the other hand, when the magnetic tape drive apparatus loads the LTFS type magnetic tape again, the logical device is generated again, so that the host apparatus recognizes again that the connected magnetic tape drive apparatus is the apparatus adapted to the file system.
As described above, whenever the magnetic tape drive apparatus loads the LTFS type magnetic tape, the host apparatus recognizes that the magnetic tape drive apparatus is the apparatus adapted to the file system, and whenever the magnetic tape drive apparatus unloads the LTFS type magnetic tape, the host apparatus does not recognize that the magnetic tape drive apparatus is the apparatus adapted to the file system. The state in which recognition for the magnetic tape drive apparatus is frequently changed, for example, causes a problem such as complication of a control operation to the host apparatus.